A sealing device is used in a shock absorber for suppressing vibration of transportation equipment or a building, a suspension device containing this shock absorber or the like and seals working fluid stored in the shock absorber or the suspension device.
For example, a suspension device called a front fork for suspending a front wheel is installed in a saddled vehicle such as a motorcycle. The suspension device includes a suspension main body with an outer tube and an inner tube inserted in such a manner as to project from and retract into the outer tube, and the shock absorber is housed in this suspension main body.
A reservoir for temperature compensation and volume compensation is formed between the suspension main body and the shock absorber and stores working fluid and gas. A sealing device used in the suspension device prevents the leakage of the working fluid and the gas in the reservoir from the suspension main body to an outer side (atmosphere side).
JP04-32342A discloses a sealing device including an annular dust seal held on an opening end part of an outer tube and held in sliding contact with the outer peripheral surface of an inner tube, and an annular oil seal held on the opening end part of the outer tube, held in sliding contact with the outer peripheral surface of the inner tube and arranged at an inner side (working-fluid side) of the dust seal.
This sealing device scrapes off foreign substances adhering to the outer peripheral surface of the inner tube by the dust seal and scrapes off the working fluid adhering to the outer peripheral surface of the inner tube by the oil seal. In this way, the sealing device can prevent the leakage of the working fluid and the gas in the suspension main body to the outer side (atmosphere side) due to scratches on sliding surfaces of the oil seal and the inner tube caused by foreign substances and maintain the interior of the suspension main body in a sealed state.